The present invention relates to a golf ball characterized by having an aesthetically pleasing appearance while retaining an excellent flight performance.
It is known that when an object having many recesses on a spherical surface, such as a golf ball, flies through the air, airflow turbulence generally arises around the object. That is, when an object having a complex spherical shape rotates while in flight, airflow turbulence during flight is complicated and affects flight performance, including the distance traveled by the object. In this connection, most golf balls have formed on the surface thereof dimples which have a shape when viewed as a flat plane from directly above (sometimes referred to below as a “top plan view”) that is circular, and have a cross-sectional shape that describes a circular arc or a similar curved line. In other words, the inner walls of the dimples are formed as concave curved surfaces.
In addition to dimples like the above which have a planar shape that is circular, polygonal dimples having what is basically a hexagonal shape are disclosed in JP-A 2003-47674.
In this prior-art disclosure, the dimple shape is one in which the planar shape of the dimple opening where it meets land areas on the golf ball is hexagonal, but the inner wall portion of the dimple is formed as a substantially concave curved surface. In addition, U.S. Pat. No. 6,290,615 describes a golf ball having hexagonal dimples. The dimples differ from ordinary dimples in that they consist of hexagonal lattice patterns formed on a sphere by a plurality of tubular projections. The tubular projections have a cross-sectional shape that is arcuate, and so each inner wall portion of a hexagonal lattice pattern forms a curved surface.
However, the orientation of the sides on the hexagonal dimples affects the direction of flight by this prior-art golf ball; the carry of the ball and its direction of flight may differ depending on whether the direction of flight agrees with or differs from the orientation of the hexagonal sides of the dimples.